Why isn't sodium counted as a metal, and which element has anomalous density?

[Hybr!d]

Hey Guys. I got this question with these 6 elements in this table

Silver = Metal
Helium = Noble Gas
Hydrogen = Non Metal
Chlorine = Halogen
Lead = Metal
Sodium = Alkali Metal

Now the question says

Which of these are metals?

I answered: Silver, Lead

But I am wondering about Sodium can it be in the answer?

Also another question states:

Comparing the Density of the metals and non metals, Which element represents an anomaly? Why?

Density (g mL^-1)

Silver = 10.5
Helium = 0.00017
Hydrogen = 0.00008
Chlorine = 0.00291
Lead = 11.3
Sodium = 0.97

This question I don't clearly understand and I hope someone can help me!

 

[PPonte]

But I am wondering about Sodium can it be in the answer?

Sodium is a metal too.

Comparing the Density of the metals and non metals, Which element represents an anomaly? Why?

Density (g mL^-1)

Silver = 10.5
Helium = 0.00017
Hydrogen = 0.00008
Chlorine = 0.00291
Lead = 11.3
Sodium = 0.97

Metals:
Silver = 10.5
Lead = 11.3
Sodium = 0.97

Non metals:
Helium = 0.00017
Hydrogen = 0.00008
Chlorine = 0.00291

I don't see any anomality. Maybe they want you to answer sodium, but I don't see it as an anomality. It has a lower density than lead and silver because it has less protons and neutrons, which is the same to say mass, per unit of volume. I'm a beginner, I just tried to help. Wait for the experts.

 

[Hybr!d]

Pponte Yeh I thought Sodium was a metal thanks for that but the last question is really bugging me.

 

[d_leet]

Metals:
Silver = 10.5
Lead = 11.3
Sodium = 0.97

Non metals:
Helium = 0.00017
Hydrogen = 0.00008
Chlorine = 0.00291

I don't see any anomality. Maybe they want you to answer sodium, but I don't see it as an anomality. It has a lower density than lead and silver because it has less protons and neutrons, which is the same to say mass, per unit of volume. I'm a beginner, I just tried to help. Wait for the experts.

Yes but because it has fewer electrons, protons and neutrons it must also have a smaller volume, which means that logically it's density shouldn't be that far off from the other metals but since it is, it is an anomaly.

 

[Hybr!d]

Ahh thanks guys you are real champs..